Buttonhole sewing machine and attachment



1969 H. EVANGELISTA' 3,425,371

BUTTONHOLE SEWING MACHINE AND ATTACHMENT Filed May 2, 1967 Sheet of 5 INVENT OR HENRY EVANGELISTA BY M$W ATTORNEYS Feb. 4, 1969 H. EVANGELISTA 3,425,371

BUTTONHOLE SEWING MACHINE AND ATTACHMENT Filed May 2, 1967 Sheet 2 0f 5 INVENT OR H EN RY EVANGELISTA BY awzm ww A'ITORN E Y5 Feb. 4, 1969 H- EV'ANGELISTA 3,425,371

BUTTONHOLE SEWING MAGHINE AND ATTACHMENT Filed May 2, 1967 Sheet 3 of 5 Fluit: a-(maaw 4 INVENTOR HENRY EVANGELIST A ATTORNEYS United States Patent 3,425,371 BUTTONHOLE SEWING MACHINE AND ATTACHMENT Henry Evangelista, 1812 2nd Ave., Altoona, Pa. 16602 Filed May 2, 1967, Ser. No. 635,448 US. Cl. 112-68 Int. Cl. Db 3/06, 81/00 2 Claims ABSTRACT OF THE DISCLOSURE This invention relates to sewing apparatus, and, more particularly, to buttonhole sewing machines and attachments.

Buttonhole sewing machines of the type adapted for use with attachments according to the invention are designed to perform a fully automatic, cyclic, buttonohle-forming operation. Each complete cycle comprises a sewing period in which the machine automatically sews a reinforcing seam around a closed path. This seam will define the periphery of the completed buttonhole. After the sewing portion of the cycle, the machine proceeds through the cutting period in the cycle, in which a knife blade cuts the fabric within the confines of the reinforcing seam to form the completed buttonhole, and the cycle is complete.

The programming of these machines for fully automatic operation has obvious advantages. However, the fully automatic operation also presents a serious drawback in that the machine completes its cycle even though the thread in the machine has broken, unless the operator detects the thread breakage and stops the machine. Detection of thread breakage is often overlooked. When the thread is broken and the machine is not stopped in time, the machine completes the cycle, even though there is no thread being fed into the machineto form the reinforcing seam, and the buttonhole is cut in the cutting portion of the machine cycle notwithstanding the fact that the reinforcing seam around the periphery of the buttonhole is not complete. The defective buttonhole must be repaired by sewing the remainder of the reinforcing seam by hand. Such hand sewing is tedious, time-consuming and costly work.

Accordingly, a main object of the invention is the provision of a buttonhole sewing machine and attachment in which the machine is automatically prevented from cutting a buttonhole in the fabric upon such breakage of the thread in the machine as would normally cause the buttonhole reinforcing seem to be incomplete.

Other objects of the invention, its features and advantages, will appear from the following detailed description which, when considered in connection with the accompanying drawings, discloses a preferred embodiment of the invention for purposes of illustration only and not for definition of the limits of the invention. For determining the scope of the invention, reference will be made to the appended claims.

In the drawings, wherein similar reference characters denote similar elements throughout the several views:

FIGURE 1 is a perspective view of a sewing machine attachment incorporating the principles of the present invention;

Patented Feb. 4, 1969 FIGURE 2 is a side elevational view of the sewing machine attachment of FIG. 1, shown in position on a buttonhole sewing machine;

FIGURE 3 is an enlarged, detail view showing the normal position of the parts of the apparatus of FIG. 2 when the thread is unbroken, the inventive attachment is in the inoperative position and the machine is in the cutting portion of the cycle;

FIGURE 4 is a detail view showing the position of the parts when the thread is broken, the inventive attachment is in the operative position, and the machine is in the sewing portion of the cycle;

FIGURE 5 is a detail view showing the arrangement of the parts with the thread broken, the inventive attachment in operative position, and the machine entering the cutting portion of the cycle;

FIGURE 6 is a detail view showing the position of the parts with the thread broken, the inventive attachment in operative position, and the machine in an intermediate portion of the cutting period but prevented from cutting the buttonhole; and

FIGURE 7 is a detail plan view of a portion of the knife tripping mechanism of the sewing machine of FIG- URE 2.

Referring now to the drawings in greater detail, and with particular reference to FIGURE 1, a buttonhole sewing machine attachment according to the invention is shown as comprising an elongated rigid arm member generally indicated at 10. In the embodiment illustrated, arm member 10 comprises front arm 12 and rear arm 14, which arms are fixedly secured together by a screw 16.

According to the invention, thread-engaging means are provided, associated with one end portion of the arm member, and including means for receiving sewing machine thread. In the embodiment illustrated, the threadengaging means takes the form of an elongated wire member 18 secured to arm member 10 by screw 20. Wire member 18 extends downwardly from the right end portion of arm member 10, as viewed in FIG-URE l. A downwardlyopening eye 22 is formed in wire member 18, for receiving the sewing machine thread.

According to the invention, an upwardly-opening hook is provided, associated with the end portion of arm member 10 which is opposite from the end portion associated with the thread-engaging means. In the embodiment illustrated, hook 24 is provided on the left end portion of arm member 10 as viewed in FIGURE 1. Hook 24 is formed in a hook member 26, which projects axially relative to arm member 10, as shown. Hook member 26 includes an axially extending slot 28. Hook member 26 is adjustably secured to rear arm 14 by screw 30, which projects through the slot 28. For purposes of adjustment, the position of the hook member can be adjusted axially relative to arm member 10, and can also be pivotally adjusted about the bolt 30, merely by loosening the screw 30, placing the hook member in the desired disposition, then tightening the screw. Such adjustment features are advantageous in that the attachment can be made to precisely fit the individual machine with which it is to be used.

According to the invention, means are provided for attaching the arm member to a buttonhole sewing machine. Such means include means for mounting the arm member for vertical swinging movement about a pivot axis located intermediate the end of the arm member. In the embodiment illustrated, such attaching means include an elongated bracket member, generally indicated at 3-2, which comprises a plate member 34 and a brace member 36, which are rigidly secured together by a screw 38. The positions of brace 36 and plate 34 relative to each other can be adjusted by loosening screw 38, placing the parts in the desired arrangement, then tightening the screw. This feature further adds to the flexibility and adaptability of the sewing machine attachment.

An aperture 40 is provided at the upper end portion of bracket member 32 so that the device can be attached to a sewing machine by means of a screw, bolt or the like. Means located at the other end portion of bracket member 32 are provided for pivotally mounting arm member on bracket member 32 at a position intermediate the ends of the arm member. Thus, bracket member 32 and arm member 10 are secured together by bolt 41 which is loosely received in arm member 10 to permit the arm member to pivot about the bolt 41. The longitudinal axis 42 of bolt 41 thus constitutes a pivot axis for the arm member 10. Since sewing machine attachments according to the present invention are gravity-actuated, the end portion of the arm member which carries the thread-engaging means swinging vertically downwardly upon breaking of the thread in the machine as will be seen later, the moments of gravitational forces acting about the pivot axis on the arm member on the side of the pivot axis on which the end portion of the arm member associated with the thread engaging means is located is greater than the moments of gravitational forces acting about the pivot axis on the arm member on the side of the pivot axis on which the end portion of the arm member associated with the hook is located. Thus, the products of gravitational forces acting on that segment of elongated arm member 10 which lies between the pivot axis 42 and the right end of the arm member as viewed in FIG. 1, and the lever arms of those forces, are greater than the products of gravitational forces acting on that segment of the arm member lying between the pivot axis 42 and the left end of the arm member, and the lever arms through which the latter forces act. As is well understood in engineering mechanics, such a balance of moments can be obtained by manipulation of the gravitational forces which act on the respective segments of the arm member, including the mass of the arm and the mass of the parts carried by the arm, and/or by manipulation of the lever arms through which those forces act. For example, the mass of the right segment of arm member 10 and the parts carried thereby may be about ounce, and that segment may extend about four inches to the right of pivot axis 42, and the mass of the left segment of arm member 10 and the parts carried thereby may be about /2 ounce and that segment may extend about two inches to the left of the pivot axis. In such an example, not only is more mass carried by the right segment of the arm member, but also a longer lever arm is provided. But irrespective of how the balance of movements is achieved, the portion of the arm member which carries the threadengaging means must be gravity-actuated to swing downwardly about pivot axis 42 if not externally supported by the tension of thread in a sewing machine.

Referring now to FIGURE 2, the sewing machine attachment of FIGURE 1 is shown in place on a buttonhole sewing machine generally indicated at 44. Since the buttonhole sewing machine 44 is conventional, apart from the inventive attachment, only those portions of the machine 44 which are essential to understand the purposes and operation of attachments according to the invention have been illustrated for the sake of conciseness and clarity in description. One type of buttonhole sewing machine for which the attachments according to the invention are adapted for use is Model No. 71-101, manufactured by the Singer Manufacturing Company, New York, New York.

The sewing machine illustrated in FIGURE 2 is of the type including a buttonhole cutting knife 46 which is secured in a knife holder 48. Knife holder 48 is carried by vertically extending, vertically movable, elongated knife holder bar 50. Knife holder bar 50 is guided for vertical movement by sleeves 52 and 54 which are provided on the machine 44. Needle 56 is carried by needle holder 58, which is disposed behind the knife holder bar in FIGURE 2 and is operatively connected to sew the reinforcing seam around the buttonhole in a conventional manner.

A horizontally extending, elongated knife driving bar 60 is provided, pivotally mounted in a spring 59 at a location 61 intermediate its ends for vertically swinging movement. Knife driving bar 60 is operatively connected at one end (the right end as viewed in FIGURE 2) to the knife holder bar 50 to move the knife holder bar vertically upon pivotal movement of the knife driving bar. Thus, knife driving bar 60 is connected to knife holder bar 50 through link 62 and sleeve member 64. Sleeve member 64 is fixedly secured to knife holder bar 50, and is pivotally connected to the lower end of link 62. The upper end of link 62 is pivotally connected to knife driving bar 60 so that vertically swinging movement of the right end portion of knife driving bar 60 is translated into vertical movement of the knife holder bar 50.

The other end of knife driving bar 60 carries a screw stud 66 which projects laterally through and beyond a slot 67 in the upper end of an elongated, vertically extending connecting link 68. Stud 66 is slidably received in slot 67. The lower end of connecting link 68 is pivotally connected at 70 to one end of a horizontally extending, elongated knife driving lever 72. The knife driving lever 72 is pivotally mounted at 74, intermediate its ends, for vertical swinging movement. The other end of knife driving bar 72 is operatively connected at 76 for vertically downward movement by shaft 77 in the cutting portion of the machine cycle in the conventional manner.

A knife bar disengaging lever 78 is provided, pivotally mounted at 79 on the connecting link 68. The knife bar disengaging lever 78 has a vertically extending arm 80 and a horizontally extending arm 82. As is best seen in FIGURE 3, the vertically extending arm 80 has at its upper end a recessed portion 84 positioned to engage from below the stud 66 on the knife driving bar when the disengaging lever is in an inoperative position. In FIGURE 3, vertically extending arm 80 is shown with the horizontal shoulder of recessed portion 84 engaging the lower walls of stud 66. Disengaging lever 78 is provided with a laterally projecting screw stud member 86.

As is best seen in FIGURE 4, sewing machine 44 is provided with a catch 88 which includes means engaging a lower surface of the horizontally extending arm 82 of the disengaging lever 78, for pivoting the disengaging lever to an operative position in which the vertically extending arm projects in a direction at an angle upwardly and laterally away from stud 66 on the knife driving bar 60 during the sewing portion of the machine cycle. In FIGURE 4, upwardly projecting tab 90 is shown engaging a lower surface of horizontally extending arm 82 to pivot disengaging lever 78 about pivot point 79 to a disposition in which vertically extending arm 80 projects at an angle upwardly and to the right of stud 66 on driving bar 60, as viewed in FIGURE 4. The knife disengaging lever 78 is also in the operative position in the arrangement of parts depicted in FIGURE 2. Such arrangement is the position of the parts during the sewing portion of the cycle. At the start of the cutting portion of the cycle in the normal operation of the machine, knife bar disengaging lever 78 is moved to the disposition shown in FIGURE 3, in which recessed portion 84 engages the stud 66 on knife driving bar 60. In the cutting portion of the cycle, shaft 77, operatively connected at 76 to the left end of the knife driving lever 72 as viewed in FIGURE 2, is moved abruptly downwardly, causing the right end of knife driving lever 72 to move abruptly upwardly. As can be seen from FIGURE 3, upward movement of the right end of knife driving lever 72 is translated through connecting link 68, vertically extending arm 80 of knife bar disengaging lever 78, and stud 66 to the left end of knife driving bar 60. Because knife driving bar 60 is pivoted at 61 intermediate its ends, upward movement of stud 66 is translated into downward movement of the right end of driving bar 60 (see FIG- URE 2). Downward movement of the right end of driving bar 60 is translated through link 62 and sleeve member 64 to vertically downward movement of knife holder 50 and knife 46, which cuts the buttonhole in the fabric.

It will be appreciated that in order for the foregoing sequence of operations to take place, means must be provided for moving the tab 90 laterally away from beneath the horizontally extending arm 82 of disengaging lever 78 at the end of the sewing portion of the machine cycle so that the disengaging lever 78 can pivot from the operative position of FIGURES 2 and 4 to the inoperative position shown in FIGURE 3. Accordingly, means are provided in the form of a cam member 92 which is operatively associated with arm 94 of catch 88, as will be explained with reference to FIGURES 4 and 7. As can best be seen in FIGURE 7, cam member 92 includes a tripping point 94, and is mounted on a shaft 96. Cam member 92 is operatively connected in the conventional manner to make one complete rotation in every complete sewing cycle. During the sewing portion of the cycle, follower 98, which is rigidly secured to arm 94 on catch 88, rides along the surface 99 of the cam member 92, and the projecting tab 90 of catch 88 is disposed underneath horizontally extending arm 82 on knife bar disengaging lever 78, as is shown in FIGURE 4. At the end of the sewing portion of the cycle, tripping point 94 of cam member 92 is rotated to engage follower 98, and as is best seen from FIGURE 7, moves the catch about pivot point 100 on the machine frame to move projecting tab 90 laterally away from beneath horizontally extending arm 82 of knife bar disengaging lever 78. A coil spring 102 (see FIGURE 4) secured to the machine frame and to the knife bar disengaging lever 78 then snaps the knife bar disengaging lever into the position of the parts illustrated in FIGURE 3, and the cutting portion of the cycle proceeds. At the end of the cutting portion of the cycle, vertically upward movement of the right end of knife driving lever 72 has caused vertically upward movement of connecting link 68 and knife bar disengaging lever 78 to a position in which the horizontally extending arm 82 of the knife bar disengaging lever is above the upper portion of projecting tab 90, and spring 104 which is secured to the machine frame and to catch 88, pivots catch 88 about pivot point 100 to move projecting tab 90 laterally beneath the horizontal arm 82 so that upon downward return by the machine of the right end of knife driving lever 72 to its original position and concomitant downward movement of knife bar disengaging lever 78, the tab 90 on catch 88 will engage the lower surface of horizontally extending arm 82 to again pivot the knife bar disengaging lever 78 to its operative position illustrated in FIGURES 2 and 4.

It can thus be seen that means including spring 104 are provided for pivoting the disengaging lever to an inoperative position in response to movement of the projecting tab 90 on the catch out of engagement with the horizontally extending arm of the disengaging lever. It will be recalled that, in the inoperative position of the knife bar disengaging lever 78, shown in FIGURE 3, the vertically extending arm 80 projects upwardly toward and the recessed portion 84 of the vertical arm engages at least the lower portion of stud 66 on knife driving bar 60.

The operation of the knife driving linkage thus far has been described as though the sewing attachment according to the invention was not attached to the machine. Without the attachment according to the invention, the knife operating linkage goes through the cycle described whether or not the machine is properly threaded.

As can be seen in FIGURE 2, the attachment of FIG- URE 1 is mounted on machine 44 by a screw 108. It should be observed that the attachment is shaped, as at 116, 118, 120, 122, 124, and 126 (see FIGURE 1) to conform to the contours of machine 44. Screw 108 passes through aperture 40 and is threadedly received in machine 44, to rigidly attach the bracket member 32 to the sewing machine. In the embodiment illustrated, the attachment is also secured to the sewing machine at the pivot point 61 of knife driving bar 60 by a screw which passes through aperture 41' in plate member 34 (see FIGURE 1).

As can be seen from FIGURE 2, the arm member 10 of the inventive attachment is held in an inoperative position by the tension of unbroken thread in the sewing machine. The machine is threaded in the usual manner, with thread 110 passing through thread tension discs 112, needle take-up lever 114 and needle 56, except that the thread is passed through eye 22 on wire member 18 in its path between the thread tension discs 112 and the needle take-up lever 114. While the arm member is held in inoperative position by the thread tension, the book 24 is located below and out of engagement with the laterally projecting member 86 on the disengaging lever 78. Since the moments of gravitational forces acting about the pivot axis 42 on the arm member on the side of the pivot axis on which the end portion associated with the thread-engaging means is located are greater than the moments of gravitational forces acting about the pivot axis on the arm member on the side of the pivot axis on which the end portion associated with the hook is located, the arm member is swingable by gravity in response to breaking of the thread in the machine to an operative position in which the hook 24 engages the laterally projecting member 86 on disengaging lever 78 (see FIGURE 4). In the operative position of the arm member, the disengaging lever 78 cannot pivot to its inoperative position at the end of the sewing portion of the cycle because hook 24 engages laterally projecting member 86 and acts against the force of spring 102 which would otherwise tend to snap the disengaging lever 78 into the position illustrated in FIG- URE 3 upon movement of projecting tab 90 laterally from beneath horizontally extending arm 82 of the disengaging lever. Thus, as is shown in FIGURE 5, notwithstanding the fact that projecting tab 90 has been moved from beneath the horizontally extending arm 82 of the disengaging lever 78, the vertically extending arm will not act to translate vertically upward force from knife bar driving lever 72 to upward movement of the left end of knife driving bar 60. Rather, as the cutting portion of the cycle proceeds as is best seen from FIGURE 6, connecting link 68 is moved upwardly by the action of knife driving bar 72, and stud 66 rides in the slot 67 in connecting link 68, which provides an effective lost motion connection to prevent the knife driving bar 60 from being actuated to drive the knife holder bar downwardly to cut the fabric. As can be seen in FIGURE 6, the action of hook 24 against laterally projecting member 86 causes vertical arm 80 to ride upwardly beside laterally projecting stud 66, instead of engaging member 66 on recessed portion 84 and carrying the stud 66 vertically upwardly with commensurate upward movement of the left end of knife driving bar 60, which would result in the knife being driven downwardly to cut the fabric.

It can thus be seen that sewing machine attachments according to the invention are effective to prevent the buttonhole sewing machine from cutting the fabric when a broken thread has prevented completion of the peripheral buttonhole reinforcing seam, yet do not require the stopping of the machine and rather permit the machine to complete its cycle. The device is as dependable as gravity, and the gravity-actuated, downward movement of the thread-engaging end portion of arm member 10 causes vertically upward movement of the hook 24 to engage the laterally projecting member 86 on the knife bar disengaging lever 78 whenever the thread breaks in the sewing period of the cycle. Upon later discovery of the broken thread, the machine can easily be re-threaded and the arm member 10 again pivoted down so that the hook is below and out of engagement with laterally projecting member 86, in the position illustrated in FIG- URE 2.

Although the present invention has been described and illustrated in connection with a preferred embodiment, it is to be understood that resort can be had to modifications and variations of the embodiment illustrated with out departing from the spirit of the invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the scope of the present invention as defined by the appended claims.

What is claimed is:

1. In a buttonhole sewing machine of the type including a buttonhole cutting knife,

a horizontally extending, pivotally mounted knife driving bar including an end portion connected to the knife and an opposite end portion having a laterally projecting stud,

an upwardly extending connecting link including an upper end portion having a slot receiving said stud,

a horizontally extending, pivotally mounted knife driving lever including one end portion pivotally connected to a lower end portion of the connecting link and an opposite end portion operatively connected for downward movement in a cutting portion of a machine cycle,

a knife bar disengaging lever pivotally mounted on the connecting link and having a first, upwardly extending arm and a second, horizontally extending arm, the first arm including a shoulder positioned to engage said stud when the disengaging lever is in an inoperative position, the first arm also including a lateral projection, and

catch means for moving the disengaging lever into operative position during a sewing portion of the machine cycle and into inoperative position for the cutting portion of the machine cycle,

in combination therewith, the improvement comprisan elongated, rigid, horizontally extending arm member having opposite first and second end portions,

thread-engaging means located at the first end portion of the arm member for receiving sewing machine thread,

an upwardly opening hook associated with the second end portion of the arm member.

mounting means pivotally mounting the arm member on the machine for vertical swinging movement about a pivot axis located intermediate the end portions of the arm member,

the mounting means mounting the arm member for swinging movement to an operative position with the hook engaging the lateral projection on the disengaging lever when the disengaging lever is in its operative position for preventing movement of the disengaging lever to its inoperative position,

the mounting means mounting the arm member for swinging movement to an inoperative position with the hook below and out of engagement with the lateral projection on the disengaging lever,

the arm member being held in inoperative position by tension of unbroken thread,

the rigid arm member being constructed to establish moments of gravitational forces acting about the pivot axis on the arm member on the side of the pivot axis on which the first end portion is located greater than the moments of gravitational forces on the side of the pivot axis on which the second end portion is located,

the arm member being swingable about the pivot axis to operative position solely by gravity in response to breaking of the thread, the first end portion being swingable downwardly and the second end portion being swingable upwardly to engage the hook with the lateral projection on the disengaging lever.

2. The structure of claim 1, wherein the hook includes a slot extending longitudinally relative to the arm member, and comprising releasable means received in the slot for adjustably securing the hook to the arm member, the hook being adjustable longitudinally relative to the arm member and pivotally relative to the releasable means.

References Cited UNITED STATES PATENTS 1,101,746 6/1914 Krell 11268 2,645,190 7/1953 Leonard 11268 2,681,024 6/1954 Deitch 11268 2,874,660 2/1959 Holland 1l268 PATRICK D. LAWSON, Primary Examiner.

45 H. HAMPTON HUNTER, Assistant Examiner. 

